The vacuum advance for the distributor is supposed to be on a ported line. Quick way to test the line its on...start the motor, take the vac line off going to the dist., if the tube that you took the line off of has any vac, then its the wrong tube.
Vacuum advance works to advance timing when you are on the throttle, NOT when you are idling. If the motor is at an idle, the line going to the dist wont have any vacuum on it.
Could that be why im not idleing? And have to feather the gas to stay running
1987 YJ Wrangler 4.2ltr 5 speed 4" rough country lift with 31x10.50 tires